If you want detect integer of float values, which presents as pure int or float, and presents as string values, use this functions:

<?php 
function isInteger($val)
{
    if (!is_scalar($val) || is_bool($val)) {
        return false;
    }
    if (is_float($val + 0) && ($val + 0) > PHP_INT_MAX) {
        return false;
    }
    return is_float($val) ? false : preg_match('~^((:?+|-)?[0-9]+)$~', $val);
}

function isFloat($val)
{
    if (!is_scalar($val)) {
        return false;
    }
    return is_float($val + 0);
}

foreach ([
    '11111111111111111', 11111111111111111, // > PHP_INT_MAX - presents in PHP as float 
    1, '10', '+1', '1.1', 1.1, .2, 2., '.2', '2.', 
    '-2.', '-.2', null, [], true, false, 'string'
] as $value) {
    echo $value . ':' . gettype($value) . ' is Integer? - '  . (isInteger($value) ? 'yes' : 'no') . PHP_EOL;
    echo $value . ':' . gettype($value) . ' is Float? - '  . (isFloat($value) ? 'yes' : 'no') . PHP_EOL;
}
?>